The specific aim of this Phase I study is to study the feasibility of a new low cost technology for high resolution, high sensitivity, Single Photon Emission Computed Tomography (SPECT). The principal objective of this new technology is to achieve about a factor of six higher spatial resolution (1.5mm compared to 10mm) than achieved with the existing systems. We propose using the technology we have developed for detectors at the Superconducting Super Collider (SSC) at Dallas, Texas. We have developed the capacity for producing scintillating plastic fibers which have good gamma ray conversion efficiency. Fibers with 1.0mm square cross section will be used to detect the X-rays with high conversion efficiency and high spatial resolution. Collimation of the X-rays is achieved using a lead collimator which is fabricated using techniques developed for the SSC. This collimator array is placed in front of the scintillating fiber X-ray converter to provide 70% X-ray transmission and about 1.5mm spatial resolution at the center of the system. The combination of novel X-ray detector and collimator system using this new SSC technology provides a significant advance in SPECT technology. With this development, SPECT can be extended into new fields of medical research and significantly improve existing methods of clinical diagnosis. In addition, it is anticipated that these technical advances can be achieved at the low costs associated with plastic technology.